In history, you could post questions to the students, and ask them to respond with reasons. For example, click below:
Candidate

Or you could get an article that discusses some of the things you are discussing in class and ask the students to weigh in. See the following example:
Texas vs. Johnson (1989)
Students could be required to respond to the reading and respond to a certain number of other students comments. They could respond to students in their class, or from other class periods.

You could give each student their own wikipage and have them create a site about a historic figure, or how they would organize a campaign for a candidate. The possibilities are endless. See me if you would like help setting up a wikipage lesson, or go to http://wikipages.com/site/for/teachers.

By the way, I found this great site while looking for material for this page.
http://www.landmarkcases.org/